Adapter-intermediate ring for a screw-in part of a fluid plug system

ABSTRACT

An adapter assembly having an intermediate ring and a screw-in part for a fluid plug-in system. The adapter assembly includes an externally threaded portion for threading into a threaded bore and an actuating shoulder. A receiving groove is formed in the transition between the actuating shoulder and the externally threaded portion with a first sealing ring is disposed therein. The intermediate ring fits onto the externally threaded portion and has opposing axially spaced annular portions. A first annular portion cooperates with the receiving groove and the actuating shoulder to form a first sealing chamber for the first sealing ring. A second sealing seat of a second annular portion facing away from the actuating shoulder cooperates with a surrounding surface adjacent to the bore and the externally threaded portion to form a second sealing chamber for the second sealing ring axially spaced from the first sealing chamber.

CROSS REFERENCE TO RELATED APPLICATION

This application claims priority to DE 202 14 631.6, filed Sep. 20, 2002and PCT/EP2003/009379, filed Aug. 25, 2003.

FIELD OF THE INVENTION

The present invention relates to a novel intermediate ring as an adapterfor a screw-in part of a special fluid plug-in system. The screw-in parthas a through-opening for plugging in a plug part, an externallythreaded portion for screwing into a threaded bore of a base part, anactuating shoulder enlarged in a flange-like manner and in particulardesigned as an external hexagon, and a receiving groove, formed in thetransition between the actuating shoulder and the externally threadedportion, with a sealing ring.

BACKGROUND AND SUMMARY OF THE INVENTION

Background for a plug-in system as referred to herein is described in EP0 005 865 B1, for example, but also in a number of later publications,such as EP 0 913 618 A1. In this connection, the screw-in part, whichcan also be referred to as a cap screw, is inserted with its externallythreaded portion into a threaded bore of a base part or housing part(for example of a pressure unit). The threaded bore is part of a special“shaped bore”, on the one hand a radial step surface, which togetherwith the screw-in part, or rather its end side, forms an annular chamberfor receiving a holding ring element, being formed inside this shapedbore following the internal thread. The holding ring element serves forthe positive locking of a plug part to be plugged into thethrough-opening of the screw-in part. The plug part is also removable byunscrewing the screw-in part together with the holding ring element. Onthe other hand, the shaped bore has on the mouth side a widening, which,together with the flange-like actuating shoulder (external hexagon) andthe adjacent receiving groove of the screw-in part, forms a seal chamberfor enclosed, compressed accommodation of a sealing ring. Moreover, thespecial shaped bore is designed in such a way with regard to its length,or rather depth, that on the one hand the screw-in part can be screwedin completely and tightened with the necessary torque and on the otherhand the plug part can also be plugged completely into or through intoits locked plugged-in position without colliding with the step surfacein the shaped bore.

There are now applications in practice where such a plug-in system is tobe inserted into other threaded bores, for example into a “standardbore” according to DIN 3852 (Part 1, Form Y). On the one hand, suchstandard bores have a surrounding surface directly adjacent on the mouthside without a seal widening (without chamber contour) and, on the otherhand, they are as a general rule not designed deep enough. Use of theplug-in system described has therefore previously necessitated specialadapters with, on one side a screw-in piece for the standard bore, andon the other side a lengthened portion with the shaped bore describedabove. On the connection side, toward the standard bore, such adaptershave an axial receiving chamber for a (second) sealing ring in such away that this sealing ring is enclosed when axial bearing contact ismade with the surrounding surface of the standard bore. However, suchadapters are expensive and lead to a disadvantageously large overalllength of the arrangement as a whole.

The object of the present invention is to provide a simple andcost-effective possibility for equipping any “standard bores” as wellwith a plug-in system of the type described without in so doing bringingabout an appreciable increase in overall length.

According to the invention, this is achieved by a novel adapterintermediate ring according to claim 1. Advantageous developmentfeatures are contained in the subclaims. The intermediate ring accordingto the invention, which can be fitted directly coaxially onto theexternally threaded portion of the screw-in part, consists of twoaxially opposite annular portions. The first annular portion having, onthe side facing the actuating shoulder, a first seat, which, togetherwith the receiving groove and the actuating shoulder, forms a first sealchamber for the first sealing ring located in the receiving groove. Thesecond, directly adjacent annular portion has a second seat for a secondsealing ring in such a way that, when the screw-in part is screwed intoa threaded bore (standard bore) having a surrounding surface adjacent onthe mouth side, a second seal chamber for the second sealing ring isformed between the second seat, the surrounding surface and theexternally threaded portion. On the one hand, in the region of the firstannular portion, the intermediate ring according to the invention has onthe inside for all practical purposes the sealing ring chamber contourof the special shaped bore, as the sealing ring seat correspondsessentially to the widening of the shaped bore. On the other hand, thesecond annular portion is also designed for optimum enclosure of asecond sealing ring, in fact, advantageously, in interaction with anystandard bore as well, as the seat of the second annular portioncorresponds for all practical purposes to the sealing ring chambercontour of the seal receiving chamber of known adapters.

According to the invention, the intermediate ring also acts as adistance ring at the same time, as it has an axial length, or ratherthickness, dimensioned according to the threaded bore concerned in sucha way that both on the one hand the screw-in part—if appropriatetogether with additional parts mounted thereon, such as in particularwith a plug holding element (holding ring element)—can be screwed incompletely to the requisite compression of the first sealing ring and onthe other hand an associated plug part can also be plugged completelyinto or rather through the through-opening of the screw-in part into acorrect plugged-in position. In this connection, however, thelength/thickness of the intermediate ring should also be limitedapproximately to an adequate minimum value in such a way that thescrew-in part is still located with sufficient stress-bearing threadturns, for example with at least three complete thread turns, inside thethreaded bore.

Additional, very long adapters are rendered unnecessary by theintermediate ring according to the invention. Using the simply andrapidly fitted intermediate ring, the screw-in part of the plug-insystem can advantageously be inserted directly into, for all practicalpurposes, any threaded bores. As a result, the overall length of thearrangement increases only slightly by merely the length, or ratherthickness, of the intermediate ring. The intermediate ring according tothe invention is moreover very much more cost-effective in comparisonwith known, large-volume adapters, because, with a much lower materialrequirement, it can also be manufactured more simply and more rapidly,in particular as a simple turned part made of brass, for example.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is to be explained in greater detail below by way ofexample with reference to the drawings, in which, in longitudinalsection in each case,

FIG. 1 shows a plug-in system equipped with an intermediate ringaccording to the invention in the mounted and plugged-in state of thescrew-in part and the plug part;

FIG. 2 shows the plug-in system according to FIG. 1 without the plugpart;

FIG. 3 shows a separate, enlarged illustration of the screw-in part withthe intermediate ring according to the invention;

FIG. 4 shows only the intermediate ring according to the inventionaccording to FIG. 3;

FIG. 5 shows a conventional plug-in system in the mounted and plugged-instate corresponding to FIG. 1 but without the intermediate ringaccording to the invention;

FIG. 6 shows a view corresponding to FIG. 2 in the application withoutan intermediate ring as in FIG. 5;

FIG. 7 shows a base part with a “shaped bore” adapted specially to theplug-in system;

FIG. 8 shows a base part with a “standard bore”, and

FIG. 9 shows the base part with a standard bore according to FIG. 8 withplug-in system inserted but without intermediate ring (not operational,only to illustrate the problem).

DETAILED DESCRIPTION OF THE INVENTION

In the various figures of the drawings, identical parts are alwaysprovided with the same references.

First, the plug-in system referred to here is to be explained withreference to FIGS. 5 to 7. This system consists of a screw-in part 2(cap screw) and a plug part 4 to be plugged in. The screw-in part 2 hasa through-opening 6 for plugging in the plug part 4 in the direction ofa plugging-in axis 8. The screw-in part 2 also has a sleeve-likeexternally threaded portion 10 with an actuating shoulder 12, which islocated on one side, enlarged in a flange-like manner and in particulardesigned as an external hexagon. The screw-in part 2 can be screwed withthe externally threaded portion 10 into a threaded bore 14 of a basepart 16. For sealing between the screw-in part 2 and the base part 16, asealing ring 18 is provided, which is located in a channel-likereceiving groove 20 formed in the transition between the actuatingshoulder 12 and the externally threaded portion 10. The base part 16 canbe for all practical purposes any housing part, for example a pressureunit.

In the case of the embodiment according to FIGS. 5 to 7, the threadedbore 14 is part of a shaped bore (F), which has a radially inwardlyprojecting step surface 22 below the threaded bore 14 (see FIG. 7). Anapproximately conical widening 23 (sealing ring chamber contour), which,together with the actuating shoulder 12 and the adjacent receivinggroove 20, forms a seal chamber for enclosed, compressed accommodationof the sealing ring 18, is formed in the mouth region of the shaped boreF, or rather of the threaded bore 14. In this connection, the shapedbore F is dimensioned in such a way that, in the screwed-in state of thescrew-in part 2 according to FIGS. 5 and 6, an annular chamber forreceiving a holding ring element 24 is formed axially between thescrew-in part 2, or rather its end side, and the step surface 22.Moreover, the design of the shaped bore F is adapted to the plug-insystem in such a way that, according to FIG. 5, the plugged-in plug part4 secured in a positively engaging manner against removal via theholding ring element 24 is arranged in a collision-free manner insidethe shaped bore F.

In the preferred embodiment, the holding ring element 24 is held on thescrew-in part 2 via catch means. Details of this configuration of theholding ring element 24 are contained in EP 0 913 618 A1 alreadymentioned above and the corresponding DE 297 19 247 U; reference istherefore made to these publications in full at this point.

It is now desirable in many applications for it to be possible to insertthe plug-in system described (screw-in part 2 with plug part 4) intothreaded bores of different shape as well.

FIGS. 8 and 9 illustrate by way of example a base part 16 a with astandard bore N. This may be a configuration according to DIN 3852 (Part1, Form Y). In this connection, as illustrated in FIG. 9, on the onehand the screw-in part 2 could not be screwed completely into a sealedposition, and on the other hand the plug part 4 cannot be plugged in acorrect and collision-free manner. In contrast to the shaped bore F, thestandard bore N has no chamber contour for the sealing ring 18 in themouth-side region of the threaded bore 14 a but rather a mouth-sidesurrounding surface 26, which merges directly in a sharp edge, or rathervia a slight chamfer, with the threaded bore 14 a (see FIG. 8). FIGS. 8and 9 illustrate an embodiment where the surrounding surface 26 isformed as a depression, but this can also, according to FIG. 8, be acontinuous plane surrounding surface 26 as indicated by broken lines.

In order for it now to be possible to use the plug-in system withscrew-in part 2 and plug part 4 in such standard bores N as well, anovel adapter intermediate ring 30 is proposed according to theinvention in accordance with FIGS. 1 to 4. This intermediate ring 30according to the invention can be fitted coaxially onto the externallythreaded portion 10 of the screw-in part 2 and has two axially oppositeannular portions 32 and 34 (see in particular FIG. 4). On the sidefacing the actuating shoulder 12, the first annular portion 32, togetherwith the receiving groove 20 and the actuating shoulder 12, forms afirst seal chamber 36 for the sealing ring 18, for which purpose it hasas a chamber contour a widening seat 38, which corresponds essentiallyto the widening 23 of the shaped bore F (cf. FIG. 7). The opposite,second annular portion 34 has a second seat 40 for a second sealing ring42 in such a way that, when the screw-in part 2 is screwed into thestandard bore N—see FIGS. 1 and 2—a second seal chamber 44 for thesecond sealing ring 42 is formed between the second seat 40, the boresurrounding surface 26 and the externally threaded portion 10. In thisconnection, the two sealing ring seats 38 and 40 and the associatedsealing rings 18 and 42 are designed in such a way that, in the mountedstate according to FIGS. 1 and 2, optimum compression of both sealingrings 18, 42 is achieved, and the second sealing ring 42 is compressedmainly axially essentially without radial deformation acting against theexternally threaded portion 10. By virtue of this advantageousdevelopment, damage of the second sealing ring 42 by bearing contactagainst the externally threaded portion 10 is avoided, so that as manyrepeat mounting operations as desired are possible.

As can be seen most clearly in FIG. 4, the two annular portions 32, 34of the intermediate ring 30 are separated by an internal radial annularweb 46 which divides the two sealing ring seats 38, 40 from one another.By virtue of this, each sealing ring seat 38, 40 is formed by a radialstep surface 48 or 50 and an approximately conically widening delimitingsurface 52 and 54 respectively adjacent to it on the outside.

As the first sealing ring 18 is located in the receiving groove 20, ithas a smaller diameter in the mounted state than the second sealing ring42 arranged on the externally threaded portion 10. The first annularportion 32 of the intermediate ring 30 is therefore also designed to besmaller in diameter, at least on the inside and preferably outwardly aswell, than the second annular portion 34. By virtue of this, a radial orinclined (conical) step 56 can be formed on the outside. However, thetwo sealing rings 18, 42 preferably have the same dimensions beforemounting. As the second seal chamber 44, or rather the second seat 40,has a larger diameter than the first seal chamber 36, or rather thefirst seat 38, the second sealing ring 42 is stretched during mountingin such a way that its ring cross section is reduced in a defined way.The step 56 preferably formed on the outside of the circumference of theintermediate ring 30 advantageously allows the user easily to recognizepositional accuracy when the intermediate ring 30 is fitted, in whichconnection a portion 58 of smaller outside diameter is to be directedtoward the actuating shoulder 12 and a larger portion 60 must face awayfrom the actuating shoulder 12 (cf. FIG. 3).

The intermediate ring 30 according to the invention is furthermoredimensioned with regard to its axial length, or rather thickness, Laccording to the standard bore N concerned in such a way that both onthe one hand the screw-in part 2, together with the holding ring element24 preferably mounted thereon, can be screwed in completely to therequisite compression of the first sealing ring 18 and on the other handthe associated plug part 4 can be plugged completely into or rather withthe free end through the through-opening 6 of the screw-in part 2 intoits correct plugged-in position. In this connection, however, the lengthL should also be limited approximately to an adequate minimum value insuch a way that the screw-in part 2 is with its externally threadedportion 10 still located with sufficient stress-bearing thread turns (ifmade of brass roughly three for example) inside the threaded bore 14 a.

The invention is not limited to the illustrative embodiments representedand described but also comprises all embodiments acting in the same wayaccording to the spirit of the invention. By virtue of the holding ringelement 24 being mounted on the screw-in part 2, it is also possible,for example, to insert the plug-in system (2, 4) into a threadedthrough-bore of a housing wall for example (with or without intermediatering 30 depending on mouth-side embodiment of the threaded bore), theholding ring element 24 projecting freely into an inner space because itis possible to dispense with axial support via a step surface, forexample, during plugging-in of the plug part 4. Furthermore, theintermediate ring 30 according to the invention can advantageously alsobe used in the screwing of connection pieces according to ISO 4039-2and/or connection pieces according to ISO 6149-3 into bores according toDIN 3852-1 and 2.

While the above description constitutes the preferred embodiment of thepresent invention, it will be appreciated that the invention issusceptible to modification, variation and change without departing fromthe proper scope and fair meaning of the accompanying claims.

1. An adapter assembly including an axially rigid intermediate ring anda screw-in part of a fluid plug-in system, the adapter assemblycomprising the screw-in part having a through-opening for plugging in aplug part, an externally threaded portion having an outer threaddiameter configured for screwing into a threaded bore of a base parthaving a surrounding surface adjacent to a mouth of the threaded bore,an actuating shoulder having an outer shoulder diameter being largerthan the thread diameter, a receiving groove formed in the transitionbetween the actuating shoulder and the externally threaded portion, anda first sealing ring being disposed in the receiving groove; theintermediate ring adapted to fit onto the externally threaded portionand having first and second axially opposite planar annular portions,the first planar annular portion configured to engage the actuatingshoulder, and the intermediate ring having a first sealing ring seat ona first side facing the actuating shoulder, the first sealing ring seatand the receiving groove and the actuating shoulder forming a firstsealing chamber for the first sealing ring, and the second planarannular portion being located at the terminal end of a lower ring stepextending away from the actuating shoulder and having a second sealingring seat on a side facing away from the actuating shoulder for a secondsealing ring, said second sealing ring surrounding and overlapping atleast one thread of the externally threaded portion of the screw-in partand said second sealing ring further having an axial length, in anoptimally compressed state, substantially equal to the axial length ofthe lower ring step, such that, when the screw-in part is screwed intothe threaded bore of the base part, the second sealing ring seat, thesurrounding surface adjacent to the threaded bore, and the externallythreaded portion of the screw-in part cooperate to form a second sealingchamber for the second sealing ring.
 2. The intermediate ring as claimedin claim 1, wherein the first and second sealing ring seats and theassociated first and second sealing rings are formed such that, in amounted state, the first and second sealing rings are compressed,wherein the second sealing ring is compressed axially withoutsubstantial radial deformation against the externally threaded portion.3. The intermediate ring as claimed in claim 1 further comprising thatthe first and second planar annular portions are separated by aninternal radial annular web which divides the first and second seatsfrom one another.
 4. The intermediate ring as claimed in claim 1 furthercomprising each sealing ring seat is formed by a radial step surface andan approximately conically widening delimiting surface adjacent to it onthe outside.
 5. The intermediate ring as claimed in claim 1 wherein athickness of the intermediate ring is dimensioned according to thethreaded bore such that both the screw-in part and a plug holdingelement mounted on the screw-in part can be screwed into the bore tocompress the first sealing ring and provide a gap between an end of theplug part and a bottom of the bore when the plug part is plugged intothe screw-in part and engaged with the plug holding element.
 6. Theintermediate ring as claimed in claim 1 comprising that the first planarannular portion is designed to be smaller in diameter than the secondplanar annular portion.
 7. The intermediate ring as claimed in claim 1comprising the intermediate ring formed of a turned part made of metal.8. An adapter assembly for a fluid plug-in system, comprising: ascrew-in part comprising a through-opening for plugging in a plug part,an externally threaded portion having an outer thread diameterconfigured for screwing into a threaded bore of a base part having asurrounding planar surface adjacent to a mouth of the threaded bore, anactuating shoulder having an outer shoulder diameter larger than theexternally threaded portion diameter, and a receiving groove formed inthe transition between the actuating shoulder and the externallythreaded portion; an axially rigid intermediate ring sized to fit ontothe externally threaded portion of the screw-in part, an upper planarannular portion configured to engage the actuating shoulder, an uppersealing ring seat on an upper side of the intermediate ring facing theactuating shoulder, an axially opposite lower ring step extending awayfrom the actuating shoulder, said lower ring step terminating at a lowerplanar annular portion configured to engage the planar surfacesurrounding the area adjacent to the mouth of the threaded bore, and alower sealing ring seat on a lower side of the intermediate ring betweenthe lower planar annular portion and the ring threads; an upper sealingring disposed in an upper sealing ring chamber; and a lower sealing ringdisposed in a lower sealing ring chamber, wherein the lower sealing ringsurrounds and overlaps and contacts at least one thread of theexternally threaded portion of the screw-in part, and further whereinthe axial length of the lower sealing ring in an optimally compressedstate is substantially equal to the axial length of the lower ring step;wherein the intermediate ring cooperates with the screw-in part to formthe upper sealing ring chamber defined by the upper sealing ring seat,the actuating shoulder, and the receiving groove, and further whereinthe intermediate ring cooperates with the base part to form the lowersealing chamber defined by the lower sealing ring seat, the externallythreaded portion of the screw-in part, and the planar surface adjacentto the mouth of the threaded bore.
 9. The intermediate ring as claimedin claim 8, wherein the upper and lower sealing ring seats and theassociated upper and lower sealing rings are formed such that, in amounted state, the upper and lower sealing rings are compressed, andfurther wherein the lower sealing ring is compressed axially withoutsubstantial radial deformation against the externally threaded portion.10. The intermediate ring as claimed in claim 8 further comprising theupper and lower planar annular portions being separated by an internalradial annular web which divides the upper and lower seats from oneanother.
 11. The intermediate ring as claimed in claim 8 furthercomprising each sealing ring seat being formed by a radial step surfaceand an approximately conically widening delimiting surface adjacent toit on the outside.
 12. The intermediate ring as claimed in claim 8wherein a thickness of the intermediate ring is dimensioned according tothe threaded bore such that both the screw-in part and a plug holdingelement mounted on the screw-in part can be screwed into the bore tocompress the upper sealing ring and provide a gap between an end of theplug part and a bottom of the bore when the plug part is plugged intothe screw-in part and engaged with the plug holding element.
 13. Theintermediate ring as claimed in claim 8 further comprising the upperplanar annular portion being smaller in diameter than the lower planarannular portion.
 14. The intermediate ring as claimed in claim 8 furthercomprising the intermediate ring formed of a turned part made of metal.